Scientists have successfully reconstructed the genome of Treponema pallidum from human remains approximately 5,500 years old, discovered in the Sabana de Bogotá region of Colombia, marking a profound expansion of our understanding of how long these infections have affected human populations. This bacterium is responsible for several serious infectious diseases today, including syphilis, yaws, and bejel. The groundbreaking findings, published in the prestigious journal Science, significantly extend the known genetic history of Treponema pallidum by more than 3,000 years, offering unprecedented insights into the ancient origins and diversification of these pathogens. The discovery challenges long-held assumptions about the timeline and geographical distribution of treponemal diseases, particularly within the Americas, and underscores the immense potential of paleogenomics to illuminate the complex evolutionary trajectories of human pathogens. The ancient human remains were meticulously excavated from a rock shelter known as Tequendama 1, situated near present-day Bogotá. This site has been a crucial archaeological locus, providing evidence of early human occupation in the high plains of the Colombian Andes. The dating of the remains to roughly 5,500 years ago places them firmly in the mid-Holocene period, a time of significant cultural and environmental change in the region. By identifying and reconstructing this remarkably ancient genome, researchers have not only pushed back the genetic history of Treponema pallidum but have also provided compelling evidence that treponemal diseases circulated in the Americas far earlier than previously documented, reigniting scholarly debates surrounding the "Columbian Exchange" theory of syphilis origins. "Our findings show the unique potential of paleogenomics to contribute to our understanding of the evolution of species, and potential health risks for past and present communities," stated geneticist Lars Fehren-Schmitz, a leading researcher at the University of California, Santa Cruz, and co-author of the study. This sentiment highlights the dual benefit of such research: unraveling the deep past informs our present and future strategies for public health. Understanding Treponemal Diseases: A Diverse Family of Pathogens Treponema pallidum is a fascinating and medically significant spiral-shaped bacterium, known for its ability to cause a spectrum of human diseases. Today, it exists in three closely related subspecies, each responsible for a distinct clinical manifestation. Treponema pallidum subspecies pallidum causes syphilis, a sexually transmitted infection known for its multi-stage progression and potential for severe long-term complications affecting organs, bones, and the nervous system. Treponema pallidum subspecies pertenue is the causative agent of yaws, a chronic, disfiguring skin disease primarily affecting children in tropical and subtropical regions, spread through direct skin-to-skin contact. The third subspecies, Treponema pallidum subspecies endemicum, causes bejel, or endemic syphilis, a non-venereal treponematosis found in arid regions, typically spread through non-sexual close contact within families. A fourth treponemal disease, pinta, which causes depigmentation of the skin, is caused by Treponema carateum or sometimes classified as Treponema pallidum subspecies carateum. However, a complete genome of the pathogen responsible for pinta has yet to be fully recovered, leaving crucial questions about its precise evolutionary relationships and taxonomic classification unanswered. Despite their nearly identical genetic makeup, the distinct geographical distributions, modes of transmission, and clinical presentations of these diseases have long puzzled scientists. The precise evolutionary events that led to the divergence of these different disease forms—when and how they emerged—remain subjects of intense scientific inquiry. While macroscopic skeletal remains can sometimes show tell-tale signs of infection, such as periosteal reactions or gummatous lesions, these markers are not always present or definitive. Genetics, particularly ancient DNA analysis, offers a far more precise and complex narrative, bridging the significant gaps between what physical anthropological evidence can reveal and what genomic data can confirm about disease evolution. The challenges of deciphering these evolutionary pathways are compounded by the bacteria’s delicate nature and the difficulties in recovering intact genetic material from ancient specimens. A Lost Lineage Unveiled: Rewriting the Evolutionary Tree Crucially, the ancient DNA recovered in this study confirmed its identity as belonging to the species Treponema pallidum, yet it did not precisely match any of the known modern forms that cause disease today. This finding is of paramount significance. Although closely related to contemporary strains, the ancient genome represents a distinct lineage that split off remarkably early in the bacterium’s evolutionary history. This "lost lineage" provides a missing piece in the complex puzzle of treponemal evolution. "One possibility is that we uncovered an ancient form of the pathogen that causes pinta, which we know little about, but is known to be endemic in Central to South America and causes symptoms localized to the skin," suggested Anna-Sapfo Malaspinas, a group leader at the SIB Swiss Institute of Bioinformatics and researcher at the University of Lausanne. She added, "At this time, we cannot prove this is the case, but it is a lead worth investigating further." The hypothesis that this ancient strain might be a precursor or an extinct relative of the pinta pathogen is particularly intriguing, given pinta’s historical prevalence in parts of the Americas. Based on sophisticated genetic analysis, scientists estimate that this ancient Colombian strain separated from other T. pallidum lineages approximately 13,700 years ago. This divergence predates the previously estimated timeline for the split of modern treponemal subspecies by several millennia. In stark contrast, the three modern subspecies (syphilis, yaws, and bejel) appear to have diverged much later, around 6,000 years ago. These updated timelines provide critical support for earlier research suggesting a more ancient and diverse evolutionary history for treponemal pathogens than previously understood, highlighting a deep history of diversification that was already underway in the Americas thousands of years earlier than prior genetic evidence indicated. "Current genomic evidence, along with our genome presented here, does not resolve the long-standing debate about where the disease syndromes themselves originated, but it does show there’s this long evolutionary history of treponemal pathogens that was already diversifying in the Americas thousands of years earlier than previously known," emphasized Elizabeth Nelson, a molecular anthropologist and paleopathologist at SMU. This statement underscores that while the exact geographical origin of specific clinical syndromes (like venereal syphilis) remains debated, the presence of diverse Treponema pallidum lineages in the Americas well before European contact is now firmly established. A Genetic Puzzle with Modern and Historical Implications Tracing the precise origins and evolutionary pathways of treponemal diseases is an exceptionally challenging endeavor, primarily because the bacteria exhibit an extraordinary degree of genetic similarity across their various subspecies. Simultaneously, these genetically similar pathogens spread through different mechanisms (sexual, skin-to-skin, non-sexual close contact) and can cause remarkably diverse symptoms, making their evolutionary paths particularly difficult to untangle through traditional epidemiological or paleopathological methods alone. "Our results push back the association of T. pallidum with humans by thousands of years, possibly more than 10,000 years ago in the Late Pleistocene," affirmed researcher Davide Bozzi at the University of Lausanne and SIB Swiss Institute of Bioinformatics. This timeframe connects the presence of Treponema pallidum with some of the earliest human migrations into the Americas, suggesting a very long co-evolutionary history between humans and these pathogens on the continent. The discovery significantly contributes to the ongoing "Columbian Exchange" debate, which posits that venereal syphilis was introduced to Europe from the Americas by Columbus’s sailors, or vice versa. While this specific finding doesn’t definitively settle the debate about venereal syphilis, it provides strong evidence for the deep antiquity and diversification of T. pallidum in the pre-Columbian Americas, suggesting that treponemal diseases were not solely a post-contact phenomenon. This remarkable discovery builds upon extensive long-term archaeological and genetic work conducted at the Tequendama 1 site. Earlier studies led by archaeologist Miguel Delgado of the Universidad Nacional de La Plata in Argentina, in collaboration with Fehren-Schmitz, had already provided detailed anthropological and taphonomic background on the ancient skeleton from which the genome was recovered. These foundational efforts were crucial in contextualizing the subsequent genetic analyses. An Unexpected Find in Massive DNA Data: The Power of Paleogenomics The ancient pathogen was not initially discovered through targeted screening. Instead, its presence emerged serendipitously. Researchers were primarily engaged in sequencing the individual’s DNA to study ancient human population history in the region, generating an astonishing 1.5 billion fragments of genetic data—a volume far exceeding typical ancient DNA sequencing efforts. During routine bioinformatics screening of this massive dataset, teams at the University of California, Santa Cruz, and the University of Lausanne independently detected minute but discernible traces of T. pallidum DNA. Recognizing the potential significance of this unexpected finding, the research groups decided to pool their expertise and investigate together. Despite bacterial DNA making up only a tiny fraction of the total genetic material recovered—a common challenge in ancient pathogen research where host DNA overwhelmingly dominates—the sheer depth of sequencing proved to be a decisive factor. This extensive data allowed the team to reconstruct a near-complete genome of the ancient pathogen without the need for specialized enrichment techniques, which are often employed to increase the proportion of pathogen DNA. This methodological success highlights the growing power of high-throughput sequencing and advanced bioinformatics in paleogenomics, enabling discoveries even from seemingly unpromising samples. It is also noteworthy that diseases caused by T. pallidum (bejel, yaws, and syphilis) can leave characteristic marks on bones, but only under certain conditions and not in all infected individuals. Historically, most ancient genomes of this bacterium have been recovered from teeth or bones that clearly exhibited macroscopic signs of disease. In a striking departure from this norm, the Colombian skeleton showed no visible evidence of infection on its skeletal elements. Researchers sampled a tibia, or shin bone, which is not as commonly used for ancient DNA studies as petrous bones (from the skull) or teeth, which are known for better DNA preservation. The success of this approach—recovering a high-quality pathogen genome from an asymptomatic bone—suggests that even skeletal elements without obvious disease markers can preserve invaluable genetic information, opening new avenues for future paleogenomic investigations. Why Ancient Disease History Matters Today: Implications for Public Health Understanding how infectious diseases emerged, evolved, and changed in the distant past holds profound implications for modern medicine and public health. By meticulously tracing the evolutionary histories of pathogens like Treponema pallidum, scientists hope to better anticipate how they might evolve in the future, how they might adapt to new hosts or environments, and how their virulence or transmissibility might shift. This knowledge is not merely academic; it is crucial for developing more effective diagnostic tools, therapeutic interventions, and public health strategies to prepare for and mitigate potential future health threats posed by both novel and re-emerging pathogens. The insights gained from ancient DNA studies can inform our understanding of host-pathogen interactions over millennia, offering a long-term perspective on disease ecology. Beyond the scientific implications, the research team demonstrated a deep commitment to ethical conduct and community engagement. Before publishing their results, the team proactively shared their findings with communities in Colombia, recognizing the profound importance of the discovery to the country’s medical and cultural history. They consulted extensively with local scholars, students, and Indigenous and non-Indigenous community members, engaging with various stakeholders through presentations and interviews. All required permits for the export and study of the ancient human remains were meticulously obtained. "This process was essential because the findings are deeply connected to Colombia’s medical and cultural history," stated Miguel Delgado. "Engaging scholars, students, and Indigenous and non-Indigenous community members ensures the results are ethically communicated and interpreted in partnership with local communities. This approach builds trust, supports responsible stewardship of sensitive discoveries, and reinforces local ownership of knowledge." This collaborative and ethically grounded approach sets an important precedent for future paleogenomic research involving human remains, emphasizing respect for cultural heritage and local perspectives. An International Collaboration Driving Discovery The landmark research was the product of an extensive international collaboration, bringing together a diverse team of experts from multiple disciplines and institutions. In addition to Elizabeth Nelson, Davide Bozzi, Anna-Sapfo Malaspinas, Miguel Delgado, and Lars Fehren-Schmitz, the research was co-led by Nasreen Broomandkhoshbacht, now at the University of Vermont. The broader team included Kalina Kassadjikova of the University of California, Santa Cruz; Jane Buikstra of Arizona State University, a renowned bioarchaeologist; Carlos Eduardo G. Amorim of California State University, Northridge; Melissa Estrada Pratt of the Instituto Colombiano de Antropología e Historia in Bogotá, Colombia, ensuring local expertise; Gilbert Greub of the University of Lausanne and Lausanne University Hospital in Switzerland; Nicolas Rascovan of the Institut Pasteur in Paris, an expert in ancient pathogen genomics; and David Šmajs of Masaryk University in the Czech Republic, a leading authority on Treponema pallidum genomics. This multi-institutional and multidisciplinary effort underscores the complex nature of modern scientific inquiry, where combining diverse expertise is often key to unlocking significant discoveries that bridge anthropology, genetics, infectious disease research, and public health. Post navigation A Novel Nanodisc Platform Revolutionizes the Study of Viral Proteins, Accelerating Vaccine Development
